Viscosity-responsive device



Jan. 21, .1936. H. 'r. BOOTH VISCOSITY RESPONSIVE DEVICE Filed Feb. 7, 1933 2 Sheets-Sheet 1 lNggN-roR ATTORNEYS Jan. 21, 1 936. I H BQQTH' 2,028,187

VISCOSITY RESPONSIVE DEVICE Filed Feb. 7, 1933 2 Sheets-Sheet 2 lN EN OR dlnra BY ATTORNEYS Patented Jan. 21, 1936 PATENT" OFF-ICE I 2,028,187 VISCOSITY-RESPONSIVE DEVICE Harry T. Booth, Detroit, Mich., assignor to Lubrication Control Corporation, Chicago, 111., a corporation of Delaware Application February '1, 193a, SerialNo. 655,576

'1 Claims.

This invention relates to viscosity responsive devices and has for an object a simple and emcient device responsive to variations'in viscosity of fluid flowing through the device.

In a device embodying the invention, the fluid is caused to pass successively through two ports, one comprising a; friction tube, the resistance of which to flow varies with the viscosity of the fluid and the other comprising an orifice, the resistance of which to fluid flow is substantially independent of the viscosity of the fluid, these parts being arranged in either of two orders of succession. Means are provided for regulating the pressure of the fluid supplied to the first port to maintain constant pressure in the fluid between the two ports and the pressure of the fluid supplied to the inlet port is applied to pressure responsivemeans which may be a control member or an indicator. The pressure of the fluid supplied to the inlet port is a function of the viscosity of the fluid and the control member or indicator is operated in response to changes in viscosity of the fluid. a

Such a viscosity responsive device is of utility in connection with any fluid system in which viscosity regulation is required and is of special utility in connection with the lubricating system of an intemal combustion engine to control the viscosity of the lubricant as described and claimed in the co-p'ending application of Henry B. Clarke, Serial No. 644,287, filed Nov. 25, 1932, and is also of utility for directly measuring and indicating the viscosity of fluid flowing through the device. Other objects, novel featuresand advantages of this invention will be apparent from the following speciflcation and accompanying drawings,

wherein:

Fig. 1 is a. side elevation of an automobile en gine having a lubricating system embodying the invention;

Fig. 2 isan enlarged fragmentary section on the line 2--2 of Fig. 1;

Fig. 3 is a view similar to Fig. 2 of a modified form of the invention; a

Fig. 4 is a sectional view through a modified form of the viscosimeter, and

Fig. 5 is a section on the line 5--5 of Fig. 2. The internal combustion engine ill is provided with an oil pan I I, the forward portion of which is of less depth than the rear portion. A vertical partition I2 forms'a well or pocket l2a.with the curved bottom of the forward portion of the oil pan, this partition terminating in asloping shelf l3 extending nearly to the rear wall of the pan. The bottom edge of the partition [2 engages the bottom of the oil pan, but does not make a fluid tight seal therewith. A heat exchange device or radiator I4 is suspended from the bottom of the oil pan adjacentthe front end thereof. A pipe l5 leads from the chamber formed by the partition l2 and shelf l3 to the radiator l4 and a pipe i6 leads from the radiator to a casing ll arranged in the well I211.

The casing I1 is. provided with a port l8 registering with the pipe l6 and a port is registering with a pipe 20 which leads to a pump 2| and a port 22 communicating with the interior of the well i2a. A piston 23 having heads 24 and 25 is slidably mounted in the casing l1 and controls the flow of oil into the casing through the pipe l6 and the port 22. The piston valve 23 is so designed that in one position thereof, the head 25 closes the port 22 with. the head 25 out of register with the port l8 while in another position thehead 24 closes the port 18 with the head 25 out of register with the port 22. A spring 26 interposed between the head and the hollow plug 21 closing; the right end of the casing ll 'tends to hold the piston 23 in the position shown in Fig. 2.

A branch pipe 28 leads from the pipe 20 to the left end of the casing ll. A hollow piston 29 is slidably mounted in the casing I! and is provided with radial ports 30 and 3| which communicate with peripheral grooves 32 and 33 in the outer surface of the piston (Fig. 5). The position of this piston with respect. to the pipe 28 controls the flow of oil through said pipe into the interior of the piston. The piston is provided with a friction tube which extends through the right end wall of the piston. A spring 35 is interposed between .the piston 29 and a hollow plug 36 mounted in the left end of the casing. An orifice 31 provides a port for escape of oil from the space between the piston 29 and the partition 38 arranged between the piston and the head 24, the rate of flow through the orifice and the friction tube being the same. A conduit 39 has one end in communication with the groove 33 and the other end in communication with the space be- 'of the rate of fiow through the friction tube and is a function of the oil viscosity.

When the engine is at rest, the various elements are in the position shown in Fig. 2. The

peripheral grooves 32 and 33 are in register with.

the port 30 and conduit 39 and the port 22 is closed while the port I9 is opened and all the chambers and spaces are filled with oil. On starting of the engine, oil is drawn in through the pipe l6 and delivered to the bearings and a part of the oil is delivered by way of the pipe 28 to the piston 29, thence through the friction tube 34 and orifice 31 into the well l2a. The fiow of oil 'through the device produces increase of pressure in the space between the partition 38 and piston 29 tending to move the latter to the left against action of the spring 35. Such movement of the piston cuts down the flow of oil into the piston 29 and continues until the-increased pressure in the space between the piston 29 and the partition 38 equals the strength of the spring 35 and such relationship is maintained throughout the entire operation by regulatory movement of the piston back and forth in its cylinder. The pressure in the oil flowing between the friction tube and orifice is thus maintained substantially constant.

When the oil is of high viscosity as is the case upon starting of the engine, the rate of fiow through the friction tube 34 is low by reason of the high resistance of the friction tube to oil of high viscosity and consequently the pressure within the piston is high. This pressure is applied through the conduit 39 to the head 24 to move the piston 23 to the right against the action of the spring 26, thereby closing the port [8 and opening the port 22. With this arrangement of the piston, the by-pass through the radiator is closed and oil is drawn by the pump solely from the well l2a. After a period of operation, the oil becomes of higher temperature and consequently of lower viscosity. Therefore, the resistance to flow of the friction tube 34 decreases with a corresponding decrease in the pressure of the oil in the piston 29. The piston 23 is thereupon moved to the left under the influence of the spring 26 to partially close the port 22 and partially open the port l8. In this position of the piston, oil is drawn through the radiator l4 as well as from the well l2a and the mixture thus obtained is supplied by the pump to the bearings. The addition of cooled oil tends to retard further viscosity decrease. Movement of the piston to the left continues as long as the viscosity of the oil supplied to the bearings tends to decrease and the pressure in the piston tends to decrease, thereby increasing the ratio of cooled oil in the mixture supplied to the bearings. As soon as the oil reaches the desired viscosity, further movement of the piston valve to the left ceases and the ratio of oil drawn directly from the sump and through the radiator remains constant.

Any decrease in viscosity of the oil due to change of engine speed or other cause is immediately compensated for by movement of the valve 22 to the left to increase the flow of oil through the by-pass, thereby tending to increase the ratio of cooled oil in the mixture. Any increase in viscosity is compensated for by movement of the valve 2| to the left to decrease the flow of oil through the radiator, thereby tending to decrease the ratio of cooled oil in the mixture. Such regulatory movement of the piston valve maintains the oil at proper viscosity.

The viscosity at which the oil is maintained is dependent upon the spring 26. This spring prevents any movement of the valve 23 until such time as the pressure exerted by the oil against the head 24 exceeds the strength of the spring and moves the piston to the left as soon as such pressure decreases below the strength of the spring and as the pressure exerted on the head 24 is a function of the viscosity of the oil, the spring 26 is designed to be of proper strength to insure maintenance of the oil at the desired viscosity.

If desired, there may be provided a pipe 40 leading from the space between the piston 29 and partition 28 to a pressure responsive indicator 4| suitably calibrated to give direct viscosity readings. The pressure of the oil in the space between the piston 29 and the partition 38 is directly applied to the indicator and as the pressure in this space is a function of the oil viscosity, readings of the oil viscosity may be obtained from the indicator.

The modification disclosed in Fig. 3 differs from the modification disclosed in Fig. 2 in that the piston 29 is provided in its right end wall with an orifice 31 and a friction tube 34 is provided for discharging oil from the space between the piston 29 and the partition 38. Also, the positions of the pipes l6 and 2| are interchanged and the head 25 is in register with the port l8 when the engine is at rest. In this modification, the pressure of oil in the space between the piston 29 and the partition 38 is maintained substantially constant by reason of the regulatory action of the piston 29.

As the resistance of the friction tube 34 to flow varies with the viscosity and as the oil pressure between the orifice and the friction tube is maintained constant, the rate of flow through the friction'tube varies with viscosity. As the resistance to flow of the orifice is independent of viscosity and is dependent upon rate of flow, and as the rate of fiow through the orifice is the same as through the friction tube, the pres-.

sure of the oil supplied to the friction tube is a measure of the rate of fiow and is a function of the oil viscosity. With high oil viscosity as at the starting of the engine, the rate of flow through the friction tube 34 will be low and therefore the pressure in the piston 29 will be low, and the valve 23 will remain in the position shown in Fig. 3 so that oil is drawn by the pump solely from the well l2a. As the viscosity decreases, the rate of fiow through the friction tube 34 increases with corresponding increase of pressure in the piston 29, thereby causing movement of the piston 23 to the right to partially open the port 18 and partially close the port 22, thus regulating the flow of warm and cooled oil to the bearings and maintaining constant the viscosity of the oil supplied to the bearings.

The viscosimeter disclosed in Fig. 4 is based on the same principle as just discussed. The piston 29a is slidably mounted in the casing Fla ,and oil'is supplied to the piston from the pipe 29 through the branch pipe 28 and port 3la. From the interior of the piston 29a, the oil flows through the orifice 31a and escapes from the casing'through the friction tube 34a. The spring 35a cooperates with the piston to maintain constant pressure in the space between the orifice 31 and the friction tube 34a. The pressure in the piston 29a is applied to the indicator Ma through the conduit 39a and pipe 40a. As the oil pressure in the piston 29a is a function of its viscosity, the indicator Ma gives direct readings of viscosity of the oil flowing through the device.

In each of the devices above described, the space between the friction tube and orifice constitutes a chamber having an inlet port comprising either the friction tube or orifice and an outlet port comprising either the orifice or friction tube. The pressure of the oil in this chamber is maintained constant and the pressure of the oil supplied to the inlet port is utilized either to actuate a valve for controlling flow of cool and warm oil to the pump to make up the mixture to be supplied to the bearings or to actuate an indicator which registers the viscosity of the oil or to operate both the valve and indicator. One Wall of the chamber is movable in response to pressure changes in the chamber to control the flow of oil to the inlet port to maintain constant the pressure in the chamber. In Figs. 2 and. 4, a viscosity indicator is shown as combined with the valve controlling means, but it is to be understood that the indicator is not'in any way essential to the proper functioning of the valve control means and may be eliminated. In fact, it is probable that in most installations of the device shown in these two figures, the indicator will be eliminated as the control means maintains the oil at a predetermined viscosity.

It is to be understood that various modiflcations may be made in the structure above described, without in any way departing from the spirit of the invention as defined in the appended Claims.

I claim:

1. In a fluid system, two fluid paths, a conduit with which said paths communicate, a heat exchange device in one path, a chamber having a port comprising a friction tube and another port comprising an orifice, means for supplying fluid from said conduit to one of said ports, means for regulating the pressure of the supplied fluid to maintain constant pressure within said chamber,.and valve means responsive to the pressure of the fluid supplied to the inlet port of said chamber for controlling flow through said paths.

2. In a fluid system, two fluid paths, a conduit with which said paths communicate, a heat exchange device in one path, a chamber having an inlet port comprising a friction tube and an outlet port plying fluid from said conduit to said inlet port under pressure, means for regulating the pressure of the supplied fluid to maintain constant pressure within said chamber, and valve means responsive to the pressure of the fluid supplied, to the, inlet port of said chamber for controlling flow through said paths.

3. In a fluid system, two fluid paths, a conduit with'whioh said paths communicate, a heat exchange device in one path, a chamber having an inlet orifice and a friction tube outlet, means for supplying fluid from said conduit to said orifice under pressure, means for regulating the pressure of the supplied fluid to maintain constant pressure withinsaid chamber, and valve comprising an orifice, means for supmeans responsive to the pressure of the fluid supplied to the inlet port of said .chamber for controlling flow through said paths.

4. In a fluid system, two fluid paths, a heat exchange device in one path, a casing with which said paths communicate, a conduit with which said casing communicates, a hollow piston for flowing fluid from said conduit to said casing.

port a friction tube extending through the end of said hollow piston adjacent said partition, an

outlet orifice for the space between said hollow piston and partition, and a conduit leading from the interior of said hollow piston to the space between said partition and valve piston.

, 5. In a fluid system, two fluid paths, a heat exchange device in one path, a casing with which said paths communicate, a conduit with which said. casing communicates, a hollow piston mounted in one end of the casing, a valve piston slidably mounted in the other end of the casing to control flow through said paths, a spring opposing movement ,of each piston in one direction, a partition between said piston and valve piston, co-operating ports in said casing and hollow piston to control fluid flow into the piston, means for flowing fluid from saidconduit to said casing port said hollow piston having an orifice in' the end thereof adjacent said partition, a friction tube outlet for the space between said hollow piston and partition, and a conduit leading from the interior of the hollow piston to the space between said partition and valve piston.

6. In a fluid system, a pair of fluid paths, a heat exchange device in one of said paths, a casing communicating with said paths, a conduit with which said casing communicates, a valve piston in said casing for controlling flow through said paths, a hollow piston in said casing, a partition between said hollow piston and said valve piston, a spring in each piston opposing movement thereof in one direction, co-operating ports in said casing and hollow piston to control flow into said piston, said hollow pistonhaving a passage extending through the end thereof adjacent said partition, said casing having an outlet passage for the space between said hollow piston and partition, one of said passages comprising a friction tube and the other passage comprising an orifice, and a conduit leading from the interior of said hollow piston to the space between said partition and valve piston.

7. In a fluid system, a fluid path divided over a portion of its length into two channels, a heat exchange device in one channel, a chamber having inlet and outlet ports of which one comprises a friction tube and the other comprises an orifice, a branch path for by-passing fluid from said system through said chamber, means for regulating the pressure of the fluid supplied to said inlet port to maintain constant pressure within said chamber, and valve means responsive to the pressure of the fluid supplied to said inlet for controlling flow through said heat exchange device.

HARRY T. BOOTH. 

